Ball joint, especially for the steering linkage of motor vehicles

ABSTRACT

A ball joint, especially for the steering linkage of motor vehicles, in which the ball head is journaled in ball socket means provided with annularly arranged spring elements of different spring characteristics which spring elements are adapted under increasing load successively to abut a portion of the ball joint housing so that successively the spring elements of different spring characteristic become effective.

United States Patent Schmid [54] BALL JOINT, ESPECIALLY FOR THE STEERINGLINKAGE OF MOTOR VEHICLES [72] Inventor: Leopold F. Schmid,Pischekstrasse 49,

7000 Stuttgard-O, Germany [22] Filed: Mar. 31, 1970 [21] Appl. No.:24,111

[30] Foreign Application Priority Data Apr. 1, 1969 Germany ..P 19 16579.8

[52] US. Cl ..287/90 RJ, 287/87 [58] Field of Search ..287/90 A, 90 C,87

[56] References Cited UNITED STATES PATENTS 2,937,895 5/1960 Langenetal. 2s7/s7 II, vac-.114; m/

[ 51 Mar. 21, 1972 3,066,963 12/1962 Vogt ..287/87 3,160,430 12/1964Gottschaid... ..287/87 3,225,420 12/1965 Sullivan,'.lr ..287/90 A X3,273,924 9/1966 Maxeiner ..287/90 A 3,424,484 1/1969 Andexler ..287/87Primary Examiner-Andrew V. Kundrat Attorney-Walter Becker ABSTRACT Aball joint, especially for the steering linkage of motor vehicles, inwhich the ball head is journaled in ball socket means provided withannularly arranged spring elements of different spring characteristicswhich spring elements are adapted under increasing load successively toabut a portion of the ball joint housing so that successively the springelements of different spring characteristic become effective.

3 Claims, 4 Drawing Figures BALL JOINT, ESPECIALLY FOR THE STEERINGLINKAGE OF MOTOR VEHICLES The present invention relates to a ball joint,especially for the steering linkage of a motor vehicle, in which forpurposes of a play-free preloaded and yieldable mounting of the ballstud in the housing of the joint there is employed a socketshapedbearing body which consists of an elastically deformable material, forinstance, polyurethane, and which is provided with recesses formed by aplurality of spring elements which aid the elastic deformation of thebearing body.

Ball joints for steering linkages pertain to the most importantstructural elements of a motor vehicle. On one hand, they have to have ahigh degree of strength because considerable forces act upon them, andbecause a breakage of these structural elements may have catastrophicconsequences. On the other hand, these elements should be as light aspossible because, depending on their position, the weight of theseelements isonly partially or not at all cushioned. The general tendencyis to keep the non-cushioned mass of a motor vehicle as smallaspossible.

It is an object of the present invention to provide a ball joint of theabove mentioned type which will be able to reduce the shocks enteringthe joints to such an extent that the steering linkage can bedimensioned considerably weaker to save weight and manufacturing costswhile retaining the same strength as correspondingly designed prior artball joints.

This object and other objects and advantages of the inven-- tion willappear more clearly from the following specification in connection withthe accompanying drawing, in which:

FIG. 1 illustrates partly in section and partly in view a ball jointaccording to the invention for connection of a tie bar with a steeringlever connected to a shank of the axle and intended for a heavypassenger car, the illustration of FIG. 1 is approximately of naturalsize.

FIG. 2 shows the socket-shaped bearing body with the spring elementspartly in view and partly in section, the illustration of FIG. 2 is at aratio of approximately 2 l of the actual size of the bearing body.

FIG. 3 is a top view of FIG. 2.

FIG. 4 shows a graph illustrating the force-stroke relationship of thespring elements of the socket-shaped bearing body according to FIGS. 1to 3.

The above outlined objects have been realized according to the inventionby the fact that the spring elements formed by recesses of the bearingbody have a different spring characteristic and that the spacing of theupper edges of the spring elements from the supporting surface of thehousing on the joint is different and, more specifically, to such anextent that the spacing increases with the increase in the hardness ofthe spring elements. The spring elements having different springcharacteristics will spring in a manner known per se in the axialdirection of the ball stud and are annularly arranged. In the ringsformed by the annular arrangement there are combined spring elements ofthe same spring characteristic while in the outermost ring which has thelargest diameter, the softest spring elements are combined. With adecrease in the diameter of the ring, the spring elements become harder.

Referring now to the drawing in detail, each end of the tie bar isprovided with a hinge pin 7 extending in axial direction. The ball ofthe hinge pin 7 is journalled in a housing 1 which through theintervention of a threaded stud is positively and adjustably connectedto the adjacent steering element, for instance, the steering lever 3 onthe axle shank 4 on one side and the steering gear on the other side.The counter nut 2 prevents the housing 1 from rotating. The two bearingbodies 6, 8 consists of an elastically deformable material, forinstance, polyurethane. The bearing body 6 which for assembly reasons istwo-sectional, is axially held by the likewise two-sectional ring 10through the intervention of the rolled over end 11 of the housing 1. Thebearing body 6 will permit freedom of play, the preload and theyieldability of the bearing. For purposes of obtaining an optimumfunction, the bearing body 6 is provided with recesses 19, 20 24 and 25b means of which spring elements 21, 22, 23 are formed which havedifferent spring characteristics. The distance between the upper edgesl6, l7 18 of the spring elements 21, 22, 23 from the supporting surfaceof the joint housing I is of different magnitude so that in cooperationwith the different spring characteristics of the individual springelements there is obtained an ideal progressively increasing springcharacteristic when the tie bar 15 is loaded in the direction of thearrow 26. The distance or spacingl3 of the upper edge of the springelement 23 from the supporting surface 5 of the joint housing 1 isgreater than and exceeds the distance or spacing in FIGS. 2 and lidentified by reference numerals 12, 31 respectively of the upper edge17 of the spring elements 22. The upper edge 16 of the spring elements21 always engages the supporting surface 5 of the housing I because thespring elements 21 are preloaded by the amount 27. The graph of FIG. 4shows the force-stroke interrelationship and indicates that the springcharacteristic 28 of the springelements 21 is flat. When the upper edge17 of the spring elements 22 contacts the supporting surface 5 of thehousing 1, the spring characteristic 29 becomes considerably steeper;The very steep spring characteristic 30 will be obtained when the upperedge 18 of the spring element 23, which practically carries out thefunction of an elastic abutment, contacts the supporting surface 5. Thearrangement furthermore comprises a rubber sleeve 9 for sealing the balljoint 1, 7 and 14 and indicates the pivoting angle of the joint.

The advantages obtained in conformity with the invention are seenprimarily in that in view of the shock-absorbing effect realized solelyby the particular design of the socket-shaped bearing body which caneasily be produced and at low costs, the shocks entering the joints willbe reduced to such an extent that the steering linkage can bedimensioned weaker without loosing in strength over correspondingheretofore known steering linkages. In this way not only weight andmoney are saved but also the driving comfort is greatly improved.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular construction shown in the drawing butalso comprises any modifications within the scope of the appendedclaims.

What I claim is:

1. A ball joint, especially for the steering linkage of a motor vehicle,which includes: a ball head, housing means surrounding said ball head inspaced relationship thereto, and socket means of an elasticallydeformable material interposed between said housing means and the outerperipheral surface of said ball head and slidably engaging said outerperipheral surface of said ball head, said socket means comprisinggroups of tongue-shaped spring elements resulting from differingrecesses therein, the spring elements of one group having a springcharacteristic different from that of the spring elements of anothergroup, at least one free end face of the tongueshaped spring elements ofone group of spring elements being spaced from said housing means by adistance less than the distance by which the corresponding free end faceof the other group is spaced from said housing means, said groups ofspring elements being respectively annularly arranged having coincidentaxis relationship, the spring elements of said groups being adapted tospring in axial direction of said socket means, said tongue-shapedspring elements residing in groups defining concentric nested circles ofdifferent diameters, the spring elements arranged along one and the samecircle having the same spring characteristic but differing as to theirspring characteristic from the spring elements arranged along anothercircle.

2. A ball joint according to claim I, in which upper edge spacingincreases as the hardness of said spring elementsincreases with thedistance of the respective spring elements from said housing means.

3. A ball joint according to claim Lin which the spring elementsarranged along the circle with the smallest diameter are softer than thespring elements along a greater diameter circle.

1. A ball joint, especially for the steering linkage of a motor vehicle,which includes: a ball head, housing means surrounding said ball head inspaced relationship thereto, and socket means of an elasticallydeformable material interposed between said housing means and the outerperipheral surface of said ball head and slidably engaging said outerperipheral surface of said ball heaD, said socket means comprisinggroups of tongue-shaped spring elements resulting from differingrecesses therein, the spring elements of one group having a springcharacteristic different from that of the spring elements of anothergroup, at least one free end face of the tongue-shaped spring elementsof one group of spring elements being spaced from said housing means bya distance less than the distance by which the corresponding free endface of the other group is spaced from said housing means, said groupsof spring elements being respectively annularly arranged havingcoincident axis relationship, the spring elements of said groups beingadapted to spring in axial direction of said socket means, saidtongue-shaped spring elements residing in groups defining concentricnested circles of different diameters, the spring elements arrangedalong one and the same circle having the same spring characteristic butdiffering as to their spring characteristic from the spring elementsarranged along another circle.
 2. A ball joint according to claim 1, inwhich upper edge spacing increases as the hardness of said springelements increases with the distance of the respective spring elementsfrom said housing means.
 3. A ball joint according to claim 1, in whichthe spring elements arranged along the circle with the smallest diameterare softer than the spring elements along a greater diameter circle.